Hospitalization for acute cardiac and vascular disease is an excellent time to initiate smoking censsation because hospitalization requires temporary tobacco abstinence at the same time that illness increases smokers' motivation to quit. Unfortunately, at least 40% of smokers fail to quit even with optimal cognitive-behavioral counseling interventions that begin in the hospital and continue after discharge. More powerful intervention strategies are needed. Adding pharmacotherapy to behavioral counseling, which is standard practice in outpatients, has not been tested in this setting because of concern about the safety of nicotine replacement after MI. Sustained release (SR) bupropion (Zyban, Wellbutrin SR) is a non-nicotine antidepressant drug that has recently proved to be effective for smoking censsation. It appears to be safety in cardiac patients and may have the additional benefit of preventing depression, an independent predictor of cardiovascular mortality. The specific aims for this study include: 1. To evaluate the efficacy of bupropion SR compared with placebo for smoking cessation in patients hospitalized with acute cardiovascular diagnoses. All patients will receive comprehensive smoking counsenling, physician advice to quit, and self-help material. Hypothesis 1.1: The intervention group will achive a higher rate of long-term smoking cessation, as measured by the point prevalence of biochemically-confirmed tobacco abstinence at 1-year follow-up, than the control group (primary outcome measure). Hypothesis 1.2: The intervention group will achieve a higher rate of smoking cessation at the end of drug treatment, as measured by the point prevalence of biochemically-confirmed tobacco abstinence at 3 month follow-up, than the control group. Hypothesis 1.3: The intervention group will have a longer duration of tobacco abstinence after hospital discharge than the control group. 2. To establish the safety of bupropion SR in smokers hospitalized with cardiovascular disease. Hypothesis 2.1: The incidence of a combined cardiovascular endpoints (cardiac death, nonfatal MI, hospital admission for CHD or CVA, or revascularization) will be no higher in the intervention group than in the control group during treatment. Indeed, there may be a net reduction in this endpoint over 1 year. 3. To compare the effect of bupropion SR with placebo on the severity of depressive symptoms, a secondary outcome related to prognosis after hospitalization for cardiovascular disease. Hypothesis 3.1: The intervention group will have a lower prevalence than the control group of depressive symptoms at 3 month and 1 year follow-ups. 4. To compare the efficacy of bupropion SR with placebo in improving health related quality of life of smokers hospitalized with cardiovascuar disease, a secondary outcome. Hypothesis 4.1: The intervention group will have a better health-related quality of life, as measured by the SF-36, than the control group 3 months and 1 year after hospital discharge.